One of things I like in Windows is that in almost every app I can press Alt, and app's main menu becomes focused. Unfortunately this doesn't work in MATE. (I use Linux Mint 13, if that matters).

I know that I can press Alt+<letter> (say, Alt+F to open "File" menu in most apps), but, first of all, not all of apps have English menus (I'm Russian, and some apps have a Russian UI), and Alt+<non_english_letter> doesn't work. And second, I have some global shortcuts Alt+<letter>, and these shortcuts of course override the application menu selection.